Video: Robotic Ants Offer Transportation Design Tips

To navigate networks of paths, robotic ants follow trails of light instead of pheromones, and they maintain their individual orientations. Data on how these robots navigate via swarm behavior, along with the design of their trail networks, may help make human transportation networks (such as those used inside a factory) more efficient.

The robots, developed by a joint US-French research team, behave like insects but don't look like them. The researchers from the New Jersey Institute of Technology and the Research Center on Animal Cognition in Toulouse, France, built the robots to mimic a real ant colony as its members navigate a network of intersecting paths that connect food and other resources with their nests.

A study of how robotic ants navigate by following trails of light and maintaining their individual orientations to a path may help make human transportation networks more efficient.(Source: PLOS Computational Biology)

Each robotic ant is a cube measuring about 20mm per side. The robots are equipped with tiny wheels and run on two watch motors. They also have photoreceptors, infrared sensors, and transmitters to detect the starting area and target destination areas and for detecting obstacles. They were purposely designed to determine whether ants' behavior could be reproduced using a minimum amount of perceptual and cognitive abilities as they established their routes.

According to a PLOS Computational Biology article about the research team's work, the ants have been programmed to avoid obstacles, follow light trails, and move according to a "correlated random walk," a typical form of insect locomotion that is random but persists in a specific direction.

The challenge is to maintain orientation toward both the nest and the locations of resources. Real ants must do this inside trails that may stretch 250 meters (273.4 yards) away from their nest. To maintain their orientation, they use a combination of information types, such as sun position or landmarks in the environment. Some ants gather data from the structure of the trails they have built. The angles between branching trails are designed so that an ant going out to search for food and an ant returning to the nest encounter trail intersections with a different series of angles. Ants tend to pick the branch that will keep them going the closest to their original direction.

The article tells us:

An ant exiting the nest and moving toward the periphery of the network generally faces symmetrical bifurcations, i.e. the two trails that follow a bifurcation deviate by approximately 30° from the original direction of the ant. Conversely, an ant coming back to its nest faces asymmetrical bifurcations: the trail heading toward the nest after a bifurcation deviates less (~30°) from the ant's original direction than the other trail (~120°) which leads away from the nest.

The researchers tested the robotic ants' behavior in two different scenarios: with trail networks that had only symmetrical bifurcation angles, and then with trail networks that contained asymmetrical bifurcations.

The video was fascinating! The final demonstration in it, where the alternate paths sometimes got highlighted just a bit made me think about alternate routes for commuting when the primary is congested (the brightest path in this video).

Sometimes the shortest timed route is not the shortest distance if the shortest distance is heavily traveled. Applying this research will still need to take this into account.

TJ, interesting point about congestion, since the researchers' conclusions are that most ants follow where other ants have gone (via pheromones), and that combined with the right intersection design will mean that most ants take the shortest path. It makes me wonder if, for ants, there are built-in limits on hive size, so congestion of the type humans create doesn't occur.

This is fascinating, Ann. Ants honestly are some of the most amazing creatures in the natural world, even if they are also some of the most annoying. (I am fighting an ant infestation at my house at the moment, hence my irritation with the little buggers.) Though they are small, they are quite complex creatures! I am not surprised that their behavior could be used to inform technology and design in this way.

Elizabeth, thanks--isn't this one fun? We've got carpenter ants here in the redwood forest, which will eat your house almost as fast as termites do--scary things. But I find ants fascinating, too: they have technologies and what might even be called a culture, in the anthropological sense. But I digress. I found the intersection structure design the most interesting part of the study, which helps them know which way they're headed.

This article was truly fascinating. I can remember some academic institution using honeybees in order to map the fastest distance traveled between a series of flowers and applied that logic to solve complex math problems. Nature sure has a way of making things efficient.

Thanks, Cabe. This one was especially fun. I've always liked biology and nature studies in general, and am fascinated with animal behavior, and with insects--they're so ALIEN (that's both a sci-fi joke and a serious statement). Yes, I remember those honeybee studies. Another thing about insects is their intelligence, at least in the collective sense.

A lot of other topics in the article, but the distributed control discussions makes me want to build a couple hundred dumb 'bots and turn them loose in the back yard to see what kind of neural net structures they 'decide' to assemble.

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